Résumé
Irrigated agriculture in North Africa relies more and more on groundwater use, even within large-scale irrigation schemes served by surface water. In a context of complex and rapidly evolving land tenure systems, farmers access groundwater through informal local arrangements using "illicit" tubewells. We analyzed the importance of these arrangements for agricultural dynamics in the West Mitidja (Algeria) and Tadla (Morocco) irrigation schemes. These arrangements allow the survival of thousands of small farm holdings, but also favour development-oriented strategies of such farms. The analysis of these arrangements provides key elements for formulating public policies facilitating the emergence of productive farms by constantly renewing the farming population, integrating technical innovation and obtaining access to production factors. However, arrangements are also a source of vulnerability for their protagonists and the water resources exploited.